Feather & Hammer Drop on Moon

What people said

Recommends Henry · 2012-04 · Physics Stack Exchange · on “Why is the time taken for something to fall proprtional to acceleration due to gravity?”

$g$ is an acceleration. So consider another similar situation with an acceleration: suppose you have a car starting at rest but which has a steady acceleration $a$ and you want to know how much time $t$ it takes to travel a given distance $s$. Exactly the same dimensional analysis would lead to $$t \propto s^\frac{1}{2} \;a^{-\frac{1}{2}}.$$ The signs here at least are intuitively obvious: if you have to travel further then you expect the time to be longer, but if your acceleration is greater then you expect the time to be shorter. And then you come to dmckee's point: if gravity is less then (ignoring anything like air resistance) the time increases compared with what you are used to on Eart

Cites Mark Eichenlaub · 2011-04 · Physics Stack Exchange · on “Is the speed of a person falling down different if doing a forward somersault during the fall?”

The person hits the ground at the same speed in both scenarios. Once you're in the air, you fall towards the ground with a constant acceleration of about 10 m/s^2. Everything falls the same way - rocks, cannonballs, people - regardless of size or somersaulting. There may be some small effects from air resistance, but not enough to be noticeable. The sommersaulter may also land with a different orientation so that his center of mass falls a further distance. Then he could hit the ground with slightly higher speed. But basically, everything falls the same way. Check out this Youtube video [this video] of a feather and hammer falling simultaneously on the moon, which shows that heavy and light objec

Cites Mike Dunlavey · 2012-10 · Physics Stack Exchange · on “Dropping an object on the moon”

OK, here's Neil Armstrong jumping onto the moon [LINK] . Did he fall up, or down to the surface? And here's a video of Commander David Scott of Apollo 15 dropping a hammer and a feather [this video] on the moon. And here's some more [LINK] . There are lots of videos of things being thrown and dropped on the moon.

Cites John Alexiou · 2013-09 · Physics Stack Exchange · on “Parachute in vacuum”

Didn't the Apollo astronauts drop a feather and a hammer [this video] on the moon to confirm that they arrive at the same time in vacuum. Similar concept here.

Cites Alfred Centauri · 2014-06 · Physics Stack Exchange · on “Why do heavier objects fall faster in air?”

We also know that in reality a lead feather falls much faster than a duck's feather with exactly the same dimensions/structure etc No, not in reality, in air . In a vacuum, say, on the surface of the moon ( as demonstrated here [this video] ), they fall at the same rate. Is there a more formal mathematical explanation for why one falls faster than the other? If the two objects have the same shape, the drag force on the each object, as a function of speed $v$, is the same. The total force accelerating the object downwards is the difference between the force of gravity and the drag force: $$F_{net} = mg - f_d(v)$$ The acceleration of each object is thus $$a = \frac{F_{net}}{m} = g - \frac{f_d(v)}{m

Cites Robin Ekman · 2015-03 · Physics Stack Exchange · on “Relativity of simultaneity in Galileo's Leaning Tower of Pisa experiment”

Instead of talking about simultaneity you can talk about the measured time between dropping the object and falling. Indeed if an astronaut drops a feather from his left hand and a hammer from his right [this video] on the Moon, an observer in motion relative to the astronaut will not consider the astronaut to drop the objects simultaneously, nor agree that they hit the ground simultaneously. However, the observer will measure the same time for the objects to fall. This is a more clear statement of the equivalence principle: motion in gravitational fields is independent of the particle's mass. (Gravitational and inertial mass are equal.) (Note that because of time dilation the observer will not ag